间接拉伸试验条件下沥青混合料的疲劳行为

Fatigue Performance of Asphalt Mixes in Indirect Tensile Test

采用间接拉伸试验方法(IDT)分别在10,20,30℃温度条件下对AC-13,AC-20,AC-25 3种典型沥青混合料进行应力控制模式下疲劳试验,分析了温度对材料疲劳性能、疲劳特征参数的影响;提出以计算横向应变建立应变疲劳方程,并采用应变-温度-作用次数三维疲劳曲面公式对材料疲劳性能进行预估。研究表明:双对数坐标下应力与疲劳寿命存在良好的线性关系,随着温度升高,同一应力水平下3种沥青混合料的疲劳强度、疲劳寿命对应力水平的敏感性均减小;3种温度条件下建立的统一拟合应变疲劳曲线有很好的相关性,能消除温度对疲劳寿命的影响;应变疲劳曲面方程能为沥青混凝土疲劳寿命的预估提供很好的依据。

The fatigue performance tests of three typical asphalt concretes,including AC-13,AC-20 and AC-25,were carried out by the indirect tensile test in 10,20 and 30 ℃. Then the influence of different temperatures on the fatigue performance and fatigue characteristic parameters was analyzed. The equation of strain fatigue was proposed to calculate the transverse strains,and the fatigue performance of different materials was predicted by the strain-temperature-effect numbers three dimensional fatigue curved surface equation. Analysis results show that there is good linear relationship between stress level and fatigue life in double-logarithms coordinate. The fatigue strength,life and the stress level sensitivity of three kinds of asphalt mixes decrease in the same stress level as the temperature increases. The uniform fitting strain fatigue curves established at 3 different temperatures possess good correlation,which can eliminate the influence of the temperature on the fatigue life. The fatigue curve surface equation can provide fine basis for the prediction of asphalt concrete fatigue life.